Electric horns



June 14, 1960 E. J. TURNEY 2,941,198

ELECTRIC HORNS Filed Nov. 12,1958 2 Sheets-Sheet 1 I I Inventor 2/ .412 [e/c J fine/var Attorney E. J. TURNEY ELECTRIC HORNS June 14, 1960 2 Sheets-Sheet 2 Filed Nov. 12, 1958 (Se/c J Tue/Y5) tlorney United States Patent 6 ELECTRIC HORNS Eric James Turney, Dunstable, England, assignor to General Motors Corporation, Detroit, Mich, a corporation of Delaware Filed Nov. 12, 1958, Ser. No. 773,399

8- Claims. (Cl. 340-388) This invention relates to electric horns such as are used on motor road vehicles, and more particularly to a circuit breaker assembly for use in such horns.

A horn, according to the invention, has a diaphragm vibratable by an electro-magnet and a wall from which are insulated, and on which are secured by a single fastener member, a pair of contact members which form part of a circuit breaker assembly for the coil, and a resistor connected between the contact members.

The arrangement of the circuit breaker assembly em ables the number of parts and the electrical connections in electric horns to be reduced.

The scope of the invention is defined by the appended claims; and how it may be performed is hereinafter particularly described with reference to the accompanying claims, in which:

' Figure I is a side elevation of a horn according to the invention;

Figure II is a plan on the line IIII in Figure 1;

Figures III, IV and V are sections on lines III-HI IV-IV, and V-V respectively in Figure II; and

Figure VI is an enlarged view of part of Figure III.

The horn has a sound projector 1 (Fig. I) the air column of which is adapted to be vibrated at a predetermined frequency by a diaphragm 3 (Fig. III) which is separated from a flange 5 on the projector 1 by a washer 7, the diaphragm being secured between the flange 5 and a flange 9 of a casing 11 by a plurality of bolts 13. a

The casing is formed of stamped metal to have three spaced coaxial bores of decreasing diameter bounded respectively by three annular walls 15, :17, and 19. The first wall 15 is connected with the second wall 17 by a radial flat wall 2 which is substantially parallel to and spaced from the diaphragm 3, and the second wall 17 and third wall 19 are interconnected by a further radial wall 23 which is parallel to the other radial wall 21 and spaced from the diaphragm 3 to form a chamber 25 which communicates with a larger diameter chamber 27. The wall 19 which forms the smallest bore is internally threaded.

Held within the smaller chamber 25 by a retainer 29 is an electro-magnet coil assembly 31. A washer 33 is arranged between the radial wall 23 of the chamber 25 and one end or" the coil assembly, and a further washer 35 is arranged between the other end of the coil assembly and the retainer 29 which is secured to the larger radial wall 21.

A pole piece 37 is threaded into the third Wall 19 and extends partly into the smaller chamber 17, the pole piece being axially aligned with and spaced from the stem portion of an armature 39 which is provided with an enlarged headed portion 41 secured by riveting to the diaphragm 3.

Such arrangement of the parts for the horn provides a very eflicient electro-magnetic motor, the separation of the air gap between the stem portion 39 and the pole air gap. The headed portion 41 provides weight for the diaphragm 31 and its stem extends coaxially through an opening in the retainer 29. The pole piece 37 can be screwed into or out of the third wall 19 to adjust the dimension of the air gap between the stem 39 and pole piece 37 to produce the desired horn tone, the pole piece 37 then being secured in the threaded bore 19, for example by deforming a portion of the threads in its well. A mounting bracket 42 for the horn is secured by welding to the third wall 19 (Fig. I).

The winding of the coil 31 has two terminal leads 45 and 47 preferably covered with an insulator sleeve,- the first lead 45 being connected to the vehicle battery. The terminal 47 is connected to the lead 49, which is held in a clip 51, by a rivet 53. The rivet heads engage the clip 51 and terminal 47 respectively, and is insulated from the casing 11 by insulator washers 55 and 56.

The other terminal lead 47 is held in a clip 60 connected to a circuit breaker assembly 59 (Fig. IV the construction of which enables the number of terminal leads and other parts normally included within a horn to be considerably reduced. This is accomplished by piece 37 causing a high flux density through the centre mounting a first and a second contact member 61 and 63 respectively of the circuit breaker assembly one at each end of a resistor disc 65 by securing the resistor disc, the pair of members 61 and 63 and a terminal 67 for the other coil terminal lead 47 by means of a single rivet 69 on to the casing wall '21 so that the resistor disc, which is electrically insulated from the casing 11, acts as a support for the contact member 63. In order that current from the clip 60 shall not pass directly to the rivet 69, the clip and the. first contact member 61 is insulated from the rivet 69 by an integral sleeve 71 on an insulator washer 73, the washer 73 abutting the outer surface of the casing wall 21 and extending through an opening therein into a bore in the resistor disc 65. One end of the rivet 69 clamps the second contact member 63 against one end of the resistor disc 65, the shank 75 of the rivet extending through the washer sleeve 71 and the other end of the rivet clamping against said washer 73 the terminal 67 to which a lead from a battery may be connected.

The resistor disc, the first contact arm 16 and clip 60 are insulated from the casing 11 by an insulator Washer 79 which has an opening therein through which the sleeve 71 extends.

The circuit breaker assembly also comprises a laminated assembly or stack 79 in which the other ends of the two contact members 61, 63 and a support arm 81 are secured together. The members of the assembly are stacked in the following order: the support arm 81; a first insulator plate 33; the first contact member 61 which comprises a flexible element 61a and a resilient element 61b; a second insulator plate 85; the second contact arm 63; and a third insulator plate 87. The parts have aligned pairs of openings and the first insulator plate 83 has a pair of sleeves 89 integral therewith and of a length to extend through the second and first contact members 61, 63. The shanks of a pair of rivets 91 extend through the support arm 81, the sleeves 89 and through the openings in the third insulator plate 87, the opposite ends of the rivets respectively abutting the third insulator plate 87 and the support arm 81 to secure the parts together and insulate them from the support arm 81, the other end of which is riveted to the casing wall 21.

The second contact member 63 has an integral extension 93 carrying at its end a fixed contact 95; and the resilient element 61b of the first contact member has an extension 97 carrying at its end a movable contact 99 adapted to co-operate with the fixed contact 95 and normally resiliently engaged therewith. The end of latter extension 97 is overlaid by the end of the second Patented June. 14, 1960,

When the contacts 95 and 99 arediseng'aged, some current still flows through thecoil of the electro-rnagnet through the resistor disc 65. The value of this current is insutficient to hold the diaphragm against its natural resiliency.

The support arm 81 has an integral extension 191 offset towards the casing wall 21 and engageable by an adjustment screw 103 threaded in an opening therein so that the end of the second insulator plate 83 can be moved towards or away from the headed portion of the armature.

I claim:

1.- An electric horn comprising a vibratable diaphragm, an electro-magnet for vibrating said diaphragm, and a circuit breaker assembly for the coil of said electromagnet, said circuit breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm and comprising a fastener member, a pair of contact members and a resistor disc whose one end surface is separated from a wall of said horn by an insulator washer and one of said contact members and Whose other end surface supports said second contact member, said contact members, and resistor disc being secured by said single fastener member to, and insulated from, said wall of said horn.-

, 2. An electric horn comp-rising a vibratable diaphragm, an electro-magnet for vibrating said diaphragm, the armature of said magnet being fixed to said diaphragm, and a circuit breaker assembly for the coil of said electromagnet, said circuit breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm and comprising a terminal for said coil, a fastener member, a first contact member carrying a movable contact, and a second contact member carrying a fixed contact, and a resistor connected between said contact members, said terminal, contact members, and resistor being secured by said single fastener member to, and insulated from, a wall of said horn, and said armature being adapted to engage and move said first contact member to interrupt said supply.

3. An electric horn according to clairn 2 in which said resistor is a disc whose one end surface is separated by an insulator washer and said first contact member from said wall and whose other end surrace supports said second contact member.

4. An electric horn according to claim 3 in which said first contact member comprises a first element of flexible metal interposed between said resistor disc and said insulator washer, and a second resilient element which is connected to said first element and which carries said movable contact.

5. An electric horn comprising a sound projector, a vibratable diaphragm closing an open side of said projector, an electro-magnet for vibrating said diaphragm, and a circuit breaker assembly for the coil of said electromagnet, said breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm and comprising a terminal for said coil, an insulator washer, a metal rivet, an insulator sleeve, a pair of contact members and a resistor disc whose one surface is separated from a wall of the horn by said insulator washer and one of said contact members and whose other end surface supports the second of said contact members, said terminal, contact members, insulator washer, insulator sleeve, and resistor disc being secured by said single metal rivet to, and insulated from, said wall of said horn, said rivet electrically connecting said second contact to said terminal, and said insulator sleeve insulating the rivet from said resistor disc and first contact member.

6. An electric horn comprising a sound projector, a

casing, a vibratable diaphragm closing open sides of the said casing and sound projector, an electro-magnet for vibrating the diaphragm mounted within the member, the armature of said magnet being fixed to said diaphragm, and a circuit breaker assembly for the coil of said electromagnet, said circuit breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm and comprising a terminal for said coil, a metal rivet, an insulator sleeve around the shank of said rivet, an insulator washer, a first contact member carrying a movable contact, a second contact member carrying a fixed contact, and a resistor disc whose one end surface is separated from a casing wall by said insulator washer and said first contact member and Whose other end surface supports said second contact member, said terminal, contact members, insulator sleeve, insulator washer and resistor disc being secured by said rivet to, and insulated from, said casing wall, said rivet electrically connecting said second contact member to said terminal, said insulator sleeve insulating said disc and first contact member from said rivet, and said armature being adapted to engage and move said first contact member to interrupt said supply.

7. An electric horn comprising a sound projector, a casing, 21 vibratable diaphragm closing open sides of said casing and sound projector, an electro-magnet mounted within the casing, the armature of said magnet being fixed to said diaphragm and a circuit breaker assembly for the coil of said electro-magnet, said circuit breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm and comprising a terminal for said coil, a metal rivet, an insulator sleeve around the shank of said rivet, an insulator washer, a support arm, a first contact member carrying a movable contact, a second contact member carrying a fixed con tact and a resistor disc whose one end surface is separated from a casing wall by said insulator washer and said first contact member and whose other end surface supports said second contactmember, said first contact member comprising a flexible metal element and a resilient metal element connected thereto, said movable contact being carried by said resilient clement, said resilient element being adapted to be engaged and moved by said armature to interrupt said current, said terminal, contact members, insulator sleeve, insulator washer and resistor disc being secured by said rivet member to, and insulated from, said casing wall, said rivet electrically connecting said second contact member to said terminal, said insulator sleeve insulating said disc and first contact member from said rivet, said support arm having one end secured to said casing wall and the other end to said first and second contact members.

-8. An electric horn comprising a vibratable diaphragm, an electromagnet for vibrating said diaphragm, and a circuit breaker assembly for the coil of said electro'magnet, 'said'circuit breaker assembly being operative to interrupt the supply of current to said coil to effect vibration of said diaphragm, said circuit breaker assembly comprising, a fastener member, a resistor disc, first and second contact members one of which engages one end of said resistor disc and the other of which engages an opposite end of said resistor disc, a terminal engaging a side of one of said contact members opposite from the side engaging said resistor disc, and an insulator member positioned between said terminal and a wall of said horn, said fastener securing said contact members, said resistor disc and said terminal to said horn wall and being insulated therefrom.

References Cited in the file of this patent UNITED STATES PATENTS 2,803,004 White Aug. 13, 1957 

